2004 MSX 140 HO post purchase questions

[allyolds68]

First of all, thank you all for the wealth of knowledge here. This is my first post but I'm a long time lurker.

I've been running three (now 2, sold one) SLT780's for three years now. I upgraded the fuel lines, rebuilt the carbs, and over-rode the oil and fuel low level issues that were forcing it into limp mode on one. All of these were done by researching here without a need to post.

I recently picked up a clean 2004 MSX 140 HO. It appears to be unmodified, has 120 psi on all three jugs, and 251 hours. It started and idled smoothly. I did not take it out on the water as the price was right and the previous owner said it hadn't been used since 2017. Judging from the registration he gave me it's more likely 2014. I will, at a minimum, drain the old gas. An Admin here on GH and also the Polaris FB group I frequent said to run it. He's a wealth of knowledge but I always feel I need for a second opinion. I read a lot of old posts here on GH and was surprised in researching here that someone said the life of these motors is about 200-250 hours. My 97 SLT780 is showing about 530 now and doesn't appear to have been rebuilt

Is there anything anyone else recommends should be done before running this ski?

Thanks,

Mike

[K447]

- 2004 MSX 140 HO. - 251 hours. It started and idled smoothly.

- hadn't been used since 2017. Judging from the registration he gave me it's more likely 2014.

I will, at a minimum, drain the old gas.

An Admin here on GH and also the Polaris FB group I frequent said to run it. He's a wealth of knowledge but I always feel I need for a second opinion.

- someone said the life of these motors is about 200-250 hours. My 97 SLT780 is showing about 530 now and doesn't appear to have been rebuilt

Is there anything anyone else recommends should be done before running this ski?

-

Welcome.

If you have not found it already, save this link and then read up on the Ficht fuel injection and the MSX 140 related material

http://polarispwcknowledge.shorturl.com/first-things-to-do

Your SLT780 has a Fuji engine while the MSX 140 has a Polaris 'domestic' engine. The 1200 engine is bigger, heavier and puts out more power than the Fuji. 530 hours on a never rebuilt Fuji engine is impressive and nice to hear about.

When I had 1200 Ficht engines they would not reach 300 hours in my use. Frequent long cruises and we would ride two of them together. I have posted threads on here years ago about my early rebuilds, the red Ficht engine in Virage TXi and the MSX 140 black engine.

Following the link above, you will find that we consider it mandatory to reinforce the mount for the fuel pressure regulator inside the fuel pump body. The regulator can fall out at any time without warning and trigger a lean fuel condition inside the cylinders that can melt through a piston quickly.

If the fuel hoses have age hardened they should be changed. The plastic fittings at the fuel injectors are fragile so care must be taken to not crack the plastic. Replace the tiny o-rings while you are in there. And sleeve the fuel hoses so they don't rub against the injector brackets.

The MSX 140 has several aspects that were unique to the MSX. The through-hull driveshaft bearing assembly should be rebuilt every so often, measured by running hours or calendar time. If the bearing seizes it can damage the driveshaft and potentially create a sudden fast leak into the hull. It cannot be greased, just rebuilt.

There is probably a lot more tips and things to check on your new-to-you MSX 140. The way to make sure it will be a reliable ride is to do the maintenance and service work up front.

Do not wait for something to fail before paying attention. Not only might the failure create expensive damage but you could be stranded on the water.

[allyolds68]

Those are excellent writes up on the fuel pressure regulator reinforcement. Before I run it on the water I’ll make sure that is repaired as well as checking the hull bearing. It will be a good winter project.

Thank you.

[allyolds68]

So the guy I bought this MSX from clearly lied. I threw it in the water and it barely got over 3000 rpm’s. (He told me it ran fine until he stopped using it three or four years ago) So I pulled it in the shop, checked the fuel pressure, and it was zero. I tore the fuel tank out and the fuel pressure regulator was laying in the bottom of the fuel pump assembly. There’s no way it ever ran well with it that way. Someone has been in there before too because one of the bolts that holds the handlebar assembly in place was FUBAR’d. I ended up having to cut the head off the bolt to get it out. It’s easily fixable though. My guess is this happened once before and someone didn’t repair it correctly and the fuel pressure regulator just fell off again. I don’t think anyone rode it for long like that or it wouldn’t still have decent compression. The good news is there wasn’t any water in the hull but I’ll still rebuild the through hull bearing assembly this winter anyway.

[K447]

I have no idea what transpired before you purchased this machine, but I can tell you that the fuel pressure regulator can fall off at any time. Such as during the trailer ride after you picked it up. Or just heat+cold cycles while it is sitting and it just works itself looser until it is ready to drop.

I fought with an MSX 140 handlebar mount that also required a bolt head to be cut off. Nobody had touched it prior, there is a 'captive' T-nut underneath that does not actually hold itself from rotating.

http://greenhulk.net/showthread.php?t=220243&p=2423532&viewfull=1#post2423532

There are some things to be aware of as one of the bolts is also the steering stop.

http://greenhulk.net/showthread.php?t=220243&p=2423641&viewfull=1#post2423641

[allyolds68]

Yes the “captive” t-nut was no longer captive. (Just spun)

The reason I say someone had been in there before was because there was a nylock nut on it, and it was the handlebar stop one that was spinning. If that one came from the factory with a nylock nut then maybe I was the first one in there

[radio-active]

There is an extra nut on the steering stop bolt. I don't recall if it is a nylock or not.

[martincom]

Like most, I found out the hard way about the locknut on the steering stop bolt. It seems everyone of these I have done, at least one of the bolt-nuts galls. I don't waste much time fighting them. I use a hand grinder to remove the head of the bolt.

[allyolds68]

Does anyone have a spare one of these for sale? This one isn't doing much of anything anymore and I'd prefer not to have the tank jumping around

[radio-active]

Mine were failing identically. They apparently have a molding flaw.

I went to the auto parts store and bought 9" black bungee straps. I removed the hooks, folded them over and used them in place of the originals. I may have opened the holes up a bit with a drill.

[allyolds68]

Mine were failing identically. They apparently have a molding flaw.

I went to the auto parts store and bought 9" black bungee straps. I removed the hooks, folded them over and used them in place of the originals. I may have opened the holes up a bit with a drill.

sounds like an easy way to replace them. The lower straps seem fine.

[radio-active]

Check it, I can pretty much guarantee it'll be starting to fatigue at the same spot. The bungees are cheap and sturdier than the originals.

[allyolds68]

Fixed the fuel pressure regulator, put it all back together, still no fuel pressure…

I’m going to try another fuel pressure gauge first but it looks like I’ll probably be taking it apart again. I’ll start by bench testing the fuel pump while it’s still in the tank. I should be able to do the same with the fuel pressure regulator by putting air pressure to it. At this point I’ll probably put new fuel lines on it too. It’s a good thing winter lasts nine months here in upstate NY. I think I’ll need the time.

[HiPeRcO]

Fixed the fuel pressure regulator, put it all back together, still no fuel pressure…

I’m going to try another fuel pressure gauge first but it looks like I’ll probably be taking it apart again. I’ll start by bench testing the fuel pump while it’s still in the tank. I should be able to do the same with the fuel pressure regulator by putting air pressure to it. At this point I’ll probably put new fuel lines on it too. It’s a good thing winter lasts nine months here in upstate NY. I think I’ll need the time.

Is the pump turning on? Ground the brown wire.

Often the Schrader valve core sits too low to get pressed down by the fuel gauge. You can remove the core for the test.

[allyolds68]

Is the pump turning on? Ground the brown wire.

Often the Schrader valve core sits too low to get pressed down by the fuel gauge. You can remove the core for the test.

The motor's running so I assume the fuel pump is working. I only ran it for about 5-10 seconds at a time. The RPM's come up normally but obviously it isn't under load so it doesn't mean much. In my somewhat limited experience with my Mustang's EFI system a fuel pump either works or it doesn't. Low battery voltage also effects fuel pump output but I assume that since it runs the fuel injectors are working and they are more dependent on good voltage than the pump. When my alternator was shot in my Mustang the engine had no power and would hardly idle. It had fuel pressure but it was very low.

The fuel pressure gauge could definitely be the problem as it's a cheap HF unit although I did crack the schrader while it was running and I get a steady stream of gas but it doesn't seem like it's as strong as it should be. 20+ psi should be more than a steady stream 6" or so high. (totally a guess and not very scientific....lol).

As much of a PIA it is to drain the oil and fuel tank and pull everything out, I think it's going to happen again. At least I've done it now so it should take half the time. This will actually be the third time as I had the pump pick-up clocked 90 degrees off the first time and the fuel tank float wasn't facing forward. Fortunately I noticed it before putting the steering back together the last time.

Before I do anything else I'm going to back it into the water and test the TPS. They're drawing the lake down now and I won't be able to test it under load soon.